Blackwell Bridge, over the River Tees just south-west of Darlington, carried an early version of the A66 from 1922 to 1924, and the A1 from 1924 to 1965. Since the opening in 1965 of the A1(M) Darlington western bypass and its spur the A66(M), the bridge has again carried the A66 and is just east of the eastern terminal roundabout of the A66(M). With the opening in 1985 of the A66 Darlington southern bypass, the road over the bridge became capable of being regarded as part of that bypass. It also remained part of the main route into Darlington from the south - yet traffic entering the town is actually heading south-east while crossing the bridge.